Boiler displays error 11 and will not ignite; you may hear clicking from the igniter but no flame is established.

Safety first: Turn off power and close the gas isolation valve. Do not repeatedly attempt ignition if you smell gas. Ventilate the area and call a professional if gas odor persists.

• Check gas supply: Ensure the main gas cock to the boiler is fully open. Verify that other gas appliances in the home operate normally; if not, contact your gas supplier.
• Inspect condensate drain: A backed-up condensate trap can affect combustion. Remove and clean the condensate trap, flush with water, and reassemble ensuring proper seals.
• Clean ignition area (visual only): Remove the front cover (after isolating power and gas). Visually inspect the burner and ignition electrode for heavy dust or corrosion. Lightly vacuum dust from the burner area without touching the electrode or wiring.
• Reset the boiler: Restore gas and power, then reset the unit. Observe through the sight glass (if provided) for ignition. If error 11 persists, the ignition electrode or gas valve may require testing and replacement by a qualified Rinnai technician.